On Fri, Nov 8, 2013 at 11:43 AM, Smylers <smyl...@stripey.com> wrote: > > • Separate fields for discount_percentage and discount_amount. This has > the disadvantage of needing to ensure that a record doesn't have both > fields set. > > If the business concocts another discount type in future, this will > require a field for each discount type.
I'd probably actually go for this and a trigger. The particular case of discounts means it's unlikely they'll add another, and this seems like the most straightforward way to deal with it. Relational databases aren't always great for modelling things, so when it's unclear what's the best solution, it's usually best to go for simple. James
